How to Route and Compare AI Models with the OpenRouter Unified API

Managing multiple AI providers is a headache, but OpenRouter solves it by putting hundreds of models behind one API. You can switch between GPT, Claude, Llama, and more with a single parameter, and even route to the cheapest model automatically. Here is how to get started.

Step 1: Create an OpenRouter Account Go to OpenRouter.ai and sign up. Complete your profile to unlock higher rate limits, then add a small amount of credit. Many models have free or low-cost tiers, so a few dollars the first time goes a long way when you experiment on OpenRouter.

Step 2: Get Your API Key In the account menu, click “Keys” and generate an API key. Treat it like a password and store it securely. This key authorizes all your requests and is required for every call you make to the OpenRouter gateway.

Step 3: Make Your First Request OpenRouter uses an OpenAI-compatible chat completions endpoint at https://openrouter.ai/api/v1. Send a request with your chosen model identifier, such as “anthropic/claude-3.5-sonnet”, and your message. Because the format is standard, popular SDKs work with just a new base URL and key.

Step 4: Explore and Compare Models Browse the OpenRouter model list to see prices, context lengths, and capabilities side by side. Send the same prompt to different models and compare results. This transparency helps you choose the ideal model for your task without maintaining separate accounts on each provider.

Step 5: Set Up Automatic Routing To optimize cost and reliability, use OpenRouter’s routing features. Configure fallback models so that if your primary provider is down or rate-limited, requests automatically switch to a backup. You can also instruct it to prefer the cheapest model that meets a minimum quality threshold.

Step 6: Monitor Usage and Costs Head to your logs on OpenRouter to review every request, including which model served it and what it cost. Track spending over time and adjust your routing rules accordingly. With OpenRouter, you gain total flexibility over your AI stack, all through a single simple API key.